Google Cloud Unmanaged Instance Groups

Step-01: Introduction¶

Create VM Instances (VM1: e2-micro and VM2: e2-small)
Create Unmanaged Instance Group
Create Health Check
Create Firewall rule for Health Check
Create Load Balancer and Verify the traffic from LB IP to VM Instances
Clean-Up all the resources created as part of this demo

Step-02: Create VMs¶

# Set Project
gcloud config set project PROJECT_ID
gcloud config set project gcplearn9

# Create VM Instance - vm1
gcloud compute instances create vm1 \
  --zone=us-central1-a \
  --machine-type=e2-micro \
  --network-interface=subnet=default \
  --tags=http-server \
  --metadata-from-file=startup-script=webserver-install.sh 

# Create VM Instance - vm2
gcloud compute instances create vm2 \
  --zone=us-central1-a \
  --machine-type=e2-small \
  --network-interface=subnet=default \
  --tags=http-server \
  --metadata-from-file=startup-script=webserver-install.sh

Step-03: Create Unmanaged Instance Group¶

Name: umig-1
Description: unmanaged-instance-group-1
Location: us-central1(IOWA)
Zone: us-central1-a
Network: default (leave to defaults)
Subnetwork: default (leave to defaults)
VM Instances: vm1, vm2
Specify Port Name Mapping:
Port Name: webserver-port
Port Numbers: 80

Click on CREATE

# Create Unmanaged Instance Group
gcloud compute instance-groups unmanaged create umig-1 \
   --project=gcplearn9 \
   --description=unmanaged-instance-group-1 \
   --zone=us-central1-a

# Set Named ports in Unmanaged Instance Group
gcloud compute instance-groups unmanaged set-named-ports umig-1 \
   --project=gcplearn9 \
   --zone=us-central1-a \
   --named-ports=webserver-port:80

# Add VM Instances to Unmanaged Instance Group
gcloud compute instance-groups unmanaged add-instances umig-1 \
   --project=gcplearn9 
   --zone=us-central1-a \
   --instances=vm1,vm2

Step-04: Review Unmanaged Instance Group Properties¶

Go to Compute Engine -> Instance Groups -> Click on umig-1
Review the following Tabs
Overview
Details
Monitoring
Errors (Not applicable for Unmanaged Instance Groups)

Step-05: Create Health Check¶

What is Health Check?
A health check determines whether a VM instance is healthy by sending requests to the instance.
An instance is considered healthy if it returns consecutive responses within a specified time.
Health checks are used for load balancing and autoscaling managed instance groups
Go to Compute Engine -> Instance Groups -> Health Checks -> CREATE HEALTH CHECK
Name: app1-health-check
Description:
Scope: Regional
Region: us-central-1 (IOWA)
Protocol: HTTP
Port: 80
Proxy Protocol: None
Request Path: /index.html
Response: Welcome
Host HTTP Header: leave empty (leave to defaults)
Logs: Off (leave to defaults) If enabled Cloud Logging cost is going to be high

Health Criteria: Leave to defaults

# Create Health Check
gcloud compute health-checks create http app1-health-check \
   --project=gcplearn9 \
   --port=80 \
   --request-path=/index.html \
   --proxy-header=NONE \
   --response=Welcome \
   --region=us-central1 \
   --no-enable-logging \
   --check-interval=10 \
   --timeout=5 \
   --unhealthy-threshold=3 \
   --healthy-threshold=2

Click on CREATE

Step-06: Create a firewall rule to allow health check probes to connect to your app¶

Health check probes come from addresses in the ranges 130.211.0.0/22 and 35.191.0.0/16, so make sure your firewall rules allow the health check to connect.

# Create Firewall rule
gcloud compute firewall-rules create allow-health-check \
    --allow tcp:80 \
    --source-ranges 130.211.0.0/22,35.191.0.0/16 \
    --network default

Step-07: Create a Load Balancer¶

Go to Network Services -> Load Balancing -> Create Load Balancer -> HTTP(S) Load Balancing -> START CONFIGURATION
Internet facing or internal only: From internet to my VMs
Click on Continue
Name: lb-for-umig1
WARNING: Click on RESERVE SUBNET
NAME: proxy-only-subnet
IP Address: 10.0.0.0/24

Click on CREATE

Proxy-only subnet required
The proxy servers implementing your Envoy-based load balancer need IP addresses, which will be allocated automatically from a subnet that you reserve for this purpose (and this purpose only) in region "us-central1". Each proxy will use its assigned IP address when connecting to the servers implementing your backend services

Frontend Configuration¶

New Frontend IP and port
Name: fip-lb-umig
Protocol: HTTP
Network Service Tier: Premium
IP Version: IPV4
IP Address: Click on CREATE IP ADDRESS
NAME: sip-lb-umig
DESCRIPTION: sip-lb-umig
Port: 80
Click on DONE

CREATE A BACKEND SERVICE¶

Click on CREATE A BACKEND SERVICE
Name: lb-backend-umig
Description: lb-backend-umig
Backend Type: Instance Group
Protocol: HTTP
Naed Port: http
Timeout: 30
New backend: umig-1
Port Numbers: 80 (select webserver-port named port from that instance group)
Balancing mode: Utilization
Maximum backend utilization: 80
Maximum RPS: leave empty (leave to defaults)
Scope: per instance (leave to defaults)
Capacity: 100
Click on DONE
Click on CREATE
Cloud CDN: leave it unchecked (leave to defaults)
Health check: app1-health-check
Logging: leave unchecked (leave to defaults)
Security: leave unselected (leave to defaults)
Click on CREATE

Host and Path Rules¶

Mode: Simple host and path rule

Review and Finalize¶

Front End
Backend
Click on CREATE
It will take 3 to 5 minutes to create the load balancer.

Step-08: Verify Load Balancer Properties after creation¶

Go to Network Services -> Load Balancing -> lb-for-umig
Verify if Instances are Healthy

Step-09: Access Sample Application using LB IP¶

# Access Sample App
http:/;<LB-IP-ADDRESS>
http://35.209.128.93
Observation: 
1. Keep refreshing to see the output from both Virtual Machines
2. You will see output from both VMs switching

# Curl with while loop runs every 1 second
while true; do curl http://35.209.128.93/; sleep 1; done

Step-10: Clean-Up - Delete Load Balancer¶

Go to Network Services -> Load Balancing -> lb-for-unmanaged-instance-group
Click on DELETE
Select Backend services:lb-backend-umig for deletion
Leave Health Checks: app1-health-check unchecked to not to delete
Click on DELETE LOAD BALANCER AND SELECTED RESOURCES

Step-11: Clean-Up Delete Unmanaged Instance Group¶

Go to Compute Engine -> Instance Groups -> Click unmanaged-instance-group-1

Click on DELETE GROUP

# Delete Instance Group - Unmanaged
gcloud compute instance-groups unmanaged delete unmanaged-instance-group-1 \
   --project=gcplearn9 \
   --zone=us-central1-a

Step-12: Clean-Up - Delete VM Instances¶

Delete the VM instances

# Delete VM 
gcloud compute instances delete vm1 --zone=us-central1-a
gcloud compute instances delete vm2 --zone=us-central1-a

# List VMs
gcloud compute instances list --filter='name:vm1'
gcloud compute instances list --filter='name:vm2'

Step-13: Clean-Up - Release External IP Address used for LB¶

Go to VPC Networks -> External IP Addresses

Select sip-lb-umig and click on RELEASE STATIC IP ADDRESS

# Delete External Static IP Address
gcloud compute addresses delete sip-lb-umig \
   --project=gcplearn9 \
   --region=us-central1

References¶

Instance Groups